Surgical cassette

ABSTRACT

A cassette for use in combination with a surgical handpiece (10) and a control console (501) for controlling irrigation and/or aspiration fluid flows to the handpiece is disclosed, having a novel valve arrangement. The cassette comprises a housing (502) having an interface (504) adapted to be held in operative association with the control console (501). The cassette also comprises a means (516) for generating a partial vacuum through interaction with a motive force provided by the console. The valve means to control fluid flows through the cassette to the handpiece are operable by a valve actuator in the console and include a valve face (208,244) formed integrally in the interface (504) of the housing (502) and sealed by a resilient molding (262) defining a valve sealing face (235,259). &lt;IMAGE&gt;

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 07/831,766, filed Feb. 5, 1992, currentlycopending.

BACKGROUND OF THE INVENTION

Microsurgical instruments typically are used by surgeons for removal oftissue from delicate and restricted spaces in the human body,particularly in surgery on the eye, and more particularly in proceduresfor removal of the crystallin lens or the vitreous body. Suchinstruments include a control console and a surgical handpiece withwhich the surgeon dissects and removes the tissue. The handpiece has asurgical tool such as an ultrasonic microsurgical cutter for cutting orfragmenting the tissue and is connected to the control console by a longpower cable and by long conduits or flexible tubes for supplying anirrigation fluid to the surgical site and for withdrawing or aspiratingfluid and fragmented tissue from the site. The cutting, irrigation andaspiration functions of the handpiece are controlled by the remotecontrol console that not only provides power for the surgical cutter(e.g., an ultrasonically vibrated needle), but also controls the flow ofirrigation fluid and provides a source of reduced pressure (relative toatmosphere) for the aspiration of fluid and fragmented tissue. Thefunctions of the console are controlled manually by the surgeon, usuallyby means of a foot-operated switch.

The multiple connections that are required between the handpiece and theconsole for the power cable and the suction and irrigation lines havemade the preparation and interconnection of the equipment prior to thesurgical procedure extremely complex, with the resultant concerns overmaintaining the sterility of the equipment and assuring error-freeconnection. Accordingly, the typical microsurgical instruments, thefluid handling connections have come to be centralized in a "cassette"that contains in one unit all of the connections for the aspiration andirrigation lines, internal conduits for directing the flow of fluids,valves for controlling the flow of fluids into and out of the handpiece,a receptacle for aspirated fluid and tissue and may contain the tubeportion of a peristaltic pump. The cassette typically is supplied in asterile package with color-coded connecting tubing already attached.Thus, setting up the equipment requires only connecting the cassettetubing to the surgical handpiece and irrigation fluid source andinserting the cassette into a receptacle in the console. The receptaclemay contain the roller head portion of a peristaltic pump (or some otheraccess to reduced pressure), an aspiration line pressure sensor anddevices for operating the valves in the cassette and for controlling theflow of irrigation or aspiration fluids through the fluid conduitswithin the cassette. For convenience and to maintain sterility, thecassette may be discarded after a single use or sterilized and reused.

Such a cassette is disclosed, for example in Steppe, et al., U.S. Pat.No. 4,713,051. The Steppe, et al., cassette is intended to cooperatewith a control console that has the roller head element of a peristalticpump as well as protruding occluder bars that can pinch or block theinternal flexible tube conduits that carry fluids through the cassette.The cassette also has an irrigation transfer tube that vents irrigationfluid into the aspiration conduit to relieve quickly the reducedpressure created within the aspiration conduit of the cassette when theaspiration function is discontinued by the surgeon. When the cassette isinstalled in the console, an arcuate cutout on the top of the cassettecontaining the compressible tube portion of the peristaltic pump engagesthe roller head to supply a source of reduced pressure for thehandpiece. The output of the peristaltic pump is collected in a flexiblebag suspended from the cassette.

While the Steppe, et al., cassette has proved useful, the use offlexible tubes as internal fluid conduits requires accurate assembly ofthe tubes within the two-part housing of the cassette for properoperation, a complex, multi-step manufacturing process. Furthermore, themethod of occluding fluid flow by pinching the flexible tubes reliesentirely on the resilient properties and the quality of the tubes,variables that are not easily controlled during manufacture to assureconsistent, predictable performance.

Another microsurgical cassette is disclosed in Sundblom, et al., U.S.Pat. No. 4,758,238. The Sundblom, et al., cassette uses channels moldedinto the body of the cassette and sealed by a stretchable coveringgasket held taut against the molded body by a cover plate as internalfluid conduits. At certain points along the conduits, enlarged roundchambers are formed in the conduits that allow enough room for theconduit to be blocked by valve stems stretching the gasket tightlyagainst the conduit inlet to seal the conduit.

The Sundblom, et al., cassette requires not only the use of mechanicalvalves stems, but also that the gasket perform the dual function ofserving as one wall of an extensive system of fluid conduits within thecassette and as a stretchable diaphragm to block the fluid flow at theselected locations. This dual function requires expensive gasketmaterials (i.e. silicone rubber), a multi-piece cassette and demandingassembly procedures.

DeMeo, et al., U.S. Pat. No. 4,798,580, discloses a microsurgicalcassette having a peristaltic pump tube within the cassette thatcooperates with a roller drive on the console to provide a source ofreduced pressure for the aspiration function of the microsurgicalhandpiece. The DeMeo, et al., cassette has a vent for venting thesuction conduit to the atmosphere when the peristaltic pump is stopped.This vent consists of a flexible tube that is compressed and therebypinched shut by an occluder bar in the console. The occluder bar pinchesthe tube, thereby closing the vent, whenever the peristaltic pump isoperating and the bar is pulled away from the tube, thereby opening thevent, when the peristaltic pump is stopped to vent atmospheric air intothe suction line. The DeMeo, et al., cassette has an irrigation fluidconduit consisting of an inlet port for connection to a source ofirrigation fluid, an outlet port for connection to the tubing supplyingirrigation fluid to the microsurgical handpiece and a flexible tubewithin the cassette connecting the inlet port and the outlet port. Aportion of the tube can be alternatively pinched shut or opened toprevent or permit the flow of irrigation fluid by pressure from anoccluder bar similar to the vent line occluder bar. The DeMeo, et al.,cassette, by using compressible tubing as the control valves for thevent and irrigation fluid conduits and a two-part housing, has the samelimitations as the Steppe, et al. cassette discussed above.

Accordingly, a need has continued to exist for a surgical cassette thatis capable of simple and easy assembly while allowing the selection ofreliable, predictable materials and structures for each functionperformed by the cassette at the lowest possible cost.

BRIEF SUMMARY OF THE INVENTION

The present invention is intended to improve upon prior art surgicalcassettes by providing a cassette having a one-piece housing adapted tobe held in operative association with a control console. Integrallyformed channels on the external surface of the housing form three sidesof various fluid flow passages within the cassette. A plastic gasketadhered to the cassette seals the channels and forms the fourth side ofthe fluid flow passages. A pump may be self-contained within thecassette and adapted to cooperate with a source of motive powercontained in the console.

The structure of the present invention may be modified or additionalelements or structures added to adapt the cassette for use withdifferent consoles. For example, in a first embodiment, a portion of aninterface is cut away and a pump race having an arcuate indentationholds the resilient tube of a peristaltic pump. The tube is connected toan aspiration fluid flow passage and the lower portion of the tube formsa discharge line that exits the cassette. An interface area on theconsole contains the roller head assembly of a peristaltic pump that isinserted into the interface wall cutout and against the indentation whenthe cassette is installed in the console, thereby compressing andholding the tube tightly between the roller head and the pump raceindentation. The discharge line is connected to a waste containersuspended from the cassette.

In a second embodiment of the present invention, the housing contains anintegral waste container in fluid communication with the discharge line.

In contrast to the first and second embodiments, a third embodiment ofthe present invention contains an integrally formed waste containerspaced in the aspiration fluid flow passage between the aspiration fluidinlet and the pump and an aspiration fluid valve is inserted into theaspiration fluid flow passage between the aspiration fluid inlet and thewaste container.

A fourth embodiment of the present invention contains all of theelements of the first embodiment and further includes an irrigationfluid inlet and outlet and an irrigation fluid flow passage having anirrigation fluid valve and connecting the irrigation fluid inlet to theirrigation fluid outlet. The irrigation fluid outlet is connected to thesurgical handpiece by flexible tubing and the peristaltic pump dischargeline is connected to a waste container suspended from the cassette.

A fifth embodiment of the present invention contains all the elements ofthe fourth embodiment and further includes a vent conduit in theaspiration fluid flow passage between the aspiration fluid inlet and thepump tube that connects to a vent valve contained within the console.

A sixth embodiment of the present invention contains all the elements ofthe fifth embodiment except the vent valve is contained within the ventconduit and the vent conduit connects the aspiration fluid flow passageto the irrigation fluid flow passage.

A seventh embodiment of the present invention contains all the elementsof the sixth embodiment and further includes a pressure sensor containedwithin the aspiration fluid flow passage between the aspiration fluidinlet and the vent conduit that cooperates with a pressure sensor in theinterface area on the console.

An eighth embodiment of the present contains a self-winding peristalticpump tube and an internal capacitance chamber within the irrigationconduit.

The present invention eliminates the need to use flexible tubing as theinternal fluid conduits within the cassette, thereby simplifying theassembly of the cassette and reducing manufacturing costs.

Accordingly, one objective of the present invention is to provide, in asingle disposable unit, a surgical cassette containing all the necessarypassages and connections for providing fluid flow between a controlconsole and a surgical handpiece.

Another objective of the present invention is to provide a surgicalcassette that is simple and inexpensive to manufacture.

Still another objective of the present invention is to provide asurgical cassette having a one-piece housing.

Another objective of the present invention is to prove a simple surgicalcassette containing an integral waste container.

Another objective of the invention is to provide a surgical cassettehaving a simple and efficient valve for allowing the console to controlthe fluid to or from the handpiece.

Still another objective of the present invention is to provide asurgical cassette having valves that are simple to manufacture andoperate, yet provide an effective, reliable occlusion of fluid flow.

Still another objective of the present invention is to provide asurgical cassette having valves that exhibit fast response and areoperable by light load solenoids in the console.

A further objective of the present invention is to provide a surgicalcassette having valves with improved reliability.

A further objection of the present invention is to provide a surgicalcassette having a pressure sensor in a conduit connected to thehandpiece.

A further objective of the present invention is to provide a surgicalcassette having a self-winding peristaltic pump tube.

A still further objection of the present invention is to provide asurgical cassette having an internal capacitance chamber in theirrigation conduit.

Additional objects and advantages of the present invention will becomeapparent to those skilled in the art from the detailed description anddrawings that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the cassette of the present invention.

FIG. 2 is a schematic view of the first embodiment of the cassette ofthe present invention.

FIG. 3 is a schematic view of the second embodiment of the cassette ofthe present invention.

FIG. 4 is a schematic view of the third embodiment of the cassette ofthe present invention.

FIG. 5 is a schematic view of the fourth embodiment of the cassette ofthe present invention.

FIG. 6 is a schematic view of the fifth embodiment of the cassette ofthe present invention.

FIG. 7 is a schematic view of the sixth embodiment of the cassette ofthe present invention.

FIG. 8 is a schematic view of the seventh embodiment of the cassette ofthe present invention.

FIG. 9 is an exploded perspective view of a surgical instrument consoleusing the cassette of the present invention.

FIG. 10 is an exploded assembly drawing of the seventh embodiment of thecassette diagrammed schematically in FIG. 8.

FIG. 11 is a top plan view of the cassette illustrated in FIG. 10,partially cut away, with a cross sectional view of the valve andpressure sensor sealing grommet molding exploded away from the cassette.

FIG. 12 is an exploded cross section of the cassette, valve and grommetmolding of FIG. 11 taken along the line 12--12.

FIG. 13 is a top plan view of the cassette shown in FIG. 10 with the topgasket removed.

FIG. 14 is a bottom plan view of the cassette shown in FIG. 10 with thebottom gasket, diaphragm and diaphragm support removed.

FIG. 15 is a partial cross sectional view of the cassette shown in FIG.14 taken along line 15--15.

FIG. 16 is a longitudinal cross sectional view of the cassette show inFIG. 14 taken along line 16--16.

FIG. 17 is an elevational view of the interface wall of the cassetteshown in FIG. 10.

FIG. 18 is a partial cross sectional view of the cassette shown in FIG.17 taken along line 18--18.

FIG. 19 is a bottom plan view of the diaphragm support of one embodimentof the present invention.

FIG. 20 is a cross section view of the diaphragm shown in FIG. 19 takenalong line 20--20.

FIG. 21 is a top or bottom plan view of the pressure sensing diaphragmof the present invention.

FIG. 22 is a cross sectional view of the diaphragm shown in FIG. 21taken along line 22--22.

FIG. 23 is an elevational view of the molding containing the diaphragmvalves and vacuum sensor sealing grommet.

FIG. 24 is a top plan view of the molding containing the diaphragmvalves and vacuum sensor sealing grommet shown in FIG. 23.

FIG. 25 is a cross section of the molding shown in FIG. 24 taken alongline 25--25.

FIG. 26 is an elevational view of the wall of the cassette shown in FIG.10 opposite the interface wall shown in FIG. 17.

FIG. 27 is a perspective view of a surgical instrument.

FIG. 28 is an exploded perspective view of an eighth embodiment of thecassette of the present invention.

FIG. 29 is a diagrammatic perspective view of the fluid conduits of thecassette illustrated in FIG. 28.

FIG. 30 is a partial fragmentary view of an interface slot on a surgicalconsole suitable for use with the cassette illustrated in FIG. 28.

FIG. 31 is a hydraulic/pneumatic schematic view of the cassetteillustrated in FIG. 28.

FIG. 32 is an exploded cross-sectional view of the cassette of thepresent invention taken at line 32--32 in FIG. 31.

DETAILED DESCRIPTION OF THE DRAWINGS

As can be seen schematically in FIGS. 1 to 9 and 27, cassette 500 of thepresent invention generally comprises housing 502 having interface wall504 that, when cassette 500 is in use, is held within slot 505 ofconsole 501, a portion of which is indicated schematically in FIG. 9.Console 501 contains a means (not shown) for securing cassette 500 withinterface wall 504 in operative association with interface slot 505 ofconsole 501, a means (not shown) for actuating any valve or pump 516 incassette 504 or, alternatively, a source of motive power (not shown) foroperating pump 516 with cassette 504. Front wall 140, opposite interfacewall 504 contains coupling 506 having aspiration fluid inlet port 512.Pump 516 communicates with aspiration fluid inlet port 512 throughchannel 514, which is integrally formed in housing 502 and containsdischarge line 522, that also can be integrally formed in housing 502 ormay be a resilient tube. Housing 502 is preferably made ofinjection-molded medical grade plastic but other suitable materials andmanufacturing methods can also be used.

Coupling 506 may be any conventional type of coupling for making afluid-tight junction between two fluid conduits. For example, coupling506 may be a generally cylindrical fitting protruding from housing 502and having a smooth or barbed exterior as preferred. Coupling 506 may bea tapered fitting such a male or female luer connector adapted to matewith a corresponding portion of the luer connector on housing 502.Coupling 506 may also be any conventional screw coupling, clampedcoupling, quick-release hydraulic fitting or the like all of which arewell-known. A preferred coupling 506 is a cylindrical or taperedfriction fitting integrally molded in housing 502.

Pump 516 also may be a peristaltic pump, a diaphragm pump operated by amechanical plunger (not shown) driven by a mechanism (not shown) inconsole 501. Diaphragm pump 516 may also be driven by an electric motor(not shown) or an electromagnetically driven plunger (not shown) such asa solenoid-operated plunger (not shown) located in cassette 500 andsupplied with electric power from a source (not shown) located withinconsole 501. Alternatively, pump 516 may be a reciprocating piston pump,a rotary vane pump, a centrifugal pump, venturi pump or any other pumpcapable of withdrawing fluid from fluid conduit 514 and expelling thefluid through discharge line 522. However, self-priming pumps arepreferred. The flow rate and the corresponding pressure level in conduit514 may be varied by adjusting the speed of pump 516.

In a first embodiment of the present invention, illustratedschematically in FIG. 2, cassette 500 contains pump tube 518 that isheld within housing 502 and is connected on one end to aspiration fluidinlet port 512 in coupling 506 through internal conduit 514. Coupling506 is connected to aspiration line 508 of surgical handpiece 10. Tube518 is connected at the end opposite internal conduit 514 to dischargeline 522 or, alternatively, the length of tube 518 may be extended toform discharge line 522. Discharge line 522 empties into waste container118 that may be a flexible plastic bag suspended from the cassette asshown in FIG. 9 or another external container (not shown). Conduit 514is preferably integrally molded into housing 502. In particular, conduit514 may be molded as a channel in housing 502 and top gasket 136, asshown in FIG. 10, may be adhered over the channel to form sealed conduit514.

Pump 516 is a peristaltic pump consisting of compressible tube 518 thatcooperates with a roller head 520 mounted in interface slot 505 onconsole 501 and driven by a source of motive power (not shown) such asan electric motor (not shown) located within console 501. When interfacewall 504 of housing 502 is installed in interface slot 505 of console501, roller head 520 presses against tub 518. Rotation of roller head520 forces aspiration fluid through tube 518 and out discharge line 522by peristaltic action, resulting in an area of reduced pressure withintube 518 at the upstream or inlet port 512 side of roller head 520. Thereduced pressure created by the rotation of roller head 520 against tube518 draws aspiration fluid from aspiration line 508 into inlet port 512and toward roller head 520 through internal conduit 514 where theaspiration fluid is forced out discharge line 522. The speed of rollerhead 520 can be varied by devices (not shown) that are well-known in theart.

A second embodiment of the present invention, illustrated schematicallyin FIG. 3, is similar to the first embodiment, differing only in thedischarge line 522 empties into waste receptacle 524 that is integrallymolded into housing 502, rather than externally suspended bag 118.

In a third embodiment of the present invention, illustratedschematically in FIG. 4, cassette 500 contains coupling 506, aspirationfluid inlet port 512, internal conduit 514, aspiration fluid flowcontrol valve 526, aspiration fluid transfer conduit 528, integral wastereceptacle 524, suction conduit 530 and pump 516. Pump 516 withdrawsatmospheric air from waste container 524 through suction conduit 530,thereby reducing the pressure in waste container 524 and drawingaspiration fluid through aspiration line 508, inlet port 512, conduit514, valve 526 and transfer conduit 528 and into waste container 514. Inthis embodiment, it is preferred that the aspirated fluid not reach pump516 and filter 515, capable of permitting the passage of gas butexcluding liquid, such as a hydrophobic or hydrophobic/hydrophilicfilter, may be inserted in suction conduit 530. Pump 516 may be any typeof vacuum pump capable of withdrawing air from waste container 524 andproducing the reduced pressure needed for the operation of theaspiration function of surgical handpiece 10. For example, pump 516 maybe a diaphragm pump or a venturi pump. Conduits 514, 528 and 530 arepreferably integrally molded into housing 502. In particular, conduits514, 528 and 530 may be molded as open channels in housing 502 and topgasket 136, as shown in FIG. 10, may be placed over the channels to formsealed conduits.

Valve 526 preferably is located proximate to interface wall 504 ofcassette 500 so that it can be actuated by an actuation means (notshown) in console 501 and may be any type of valve that is capable ofshutting off the flow of a fluid. Thus, a sliding gate valve, a ballvalve, a stopcock or the like can be used. A preferred valve is adiaphragm valve, as illustrated in FIGS. 23, 24 and 25, wherein amovable sealing diaphragm (similar to diaphragms 234 or 258) may bemoved between an open position wherein fluid is permitted to flowthrough orifices (not shown) within valve 526 and a closed positionwherein the diaphragm (not shown) blocks the flow through at least oneof the internal orifices (not shown) of valve 526. The structure andoperation of preferred diaphragm valves is more fully described below inthe description of the seventh embodiment of the present invention.

In a fourth embodiment of the present invention, illustratedschematically in FIG. 5, cassette 500 is similar to the secondembodiment and contains all the elements of the second embodiment butfurther includes internal irrigation fluid conduits 544 and 548, andirrigation fluid valve 546 for controlling the flow of irrigation fluidto surgical handpiece 10, an irrigation fluid inlet coupling 532 havingan inlet port 536 for connection in an irrigation fluid inlet tube 534and an irrigation fluid outlet coupling 538 having an outlet port 542for connection to an irrigation fluid outlet tube 540. Couplings 532 and538 may be constructed essentially the same as coupling 506. Inlet port536 communicates with irrigation fluid inlet conduit 544 which conductsthe irrigation fluid to valve 546. Similarly, irrigation fluid outletconduit 548 conducts the irrigation fluid from valve 546 to outlet port542. Valve 546 is similar to valve 526 and actuated in the same manneras valve 526 by a control means (not shown) located in console 501.Irrigation fluid conduits 544 and 548 are preferably integrally moldedin housing 502 and constructed in the same manner as conduits 514, 528and 530.

It will be understood that, although cassette 500 of FIG. 5 containselements for performing both the irrigation and aspiration functions, itis not necessary that these elements be combined in a single cassette.Just as cassettes 500 in FIGS. 1-4 contain only elements for performingthe aspiration function, it is possible to have cassette 500 accordingto the present invention that contains only the irrigation elements(couplings 532 and 538, ports 512 and 542, irrigation fluid tubes 534and 540, conduits 544 and 548 and valve 546) of cassette 500 illustratedin FIG. 5.

A fifth embodiment of the present invention, illustrated schematicallyin FIG. 6, cassette 500 is similar to cassette 500 of the fourthembodiment described above in that cassette 500 contains elements forcontrolling the flow of aspiration and irrigation fluid. However,cassette 500 further contains a vent line 556 that intersects aspirationfluid conduit 514 between aspiration fluid inlet port 512 and pump 516at one end and terminates at a vent port 554 on interface wall 504. Ventport 554 communicates with a vent valve (not shown) located in console501 and allows the surgeon to eliminate the reduced pressure withinconduit 514 and stop the aspiration function as quickly as possible whenthe aspiration and cutting functions of handpiece 10 are suspended.

A sixth embodiment, illustrated schematically in FIG. 7, is similar tothe fifth embodiment illustrated in FIG. 6 except cassette 500 does notcontain vent port 554. Instead, vent line 556 terminates in a vent valve558 located in cassette 500. Vent valve 558 is further in communicationwith irrigation conduit 544 through irrigation vent 560. Thisarrangement of vent line, vent valve and irrigation vent permitsirrigation fluid rather than air to enter aspiration fluid conduit 514when the surgeon interrupts the cutting function of handpiece 10. Ventvalve 558 is actuated by a means (not shown) in console 501 in the samemanner as irrigation valve 546. The preferred types of vent valve 558are the same as for the irrigation valve 546 and aspiration controlvalve 526 described above.

A seventh embodiment of the present invention, illustrated schematicallyin FIG. 8 and more particularly in FIGS. 10-27, contains all theelements of the sixth embodiment described above and further includes apressure indicating chamber 164 within aspiration conduit 514 thatcooperates with a pressure sensor (not shown) in console 501 to indicatethe pressure level within conduit 514 in a manner that will be describedmore fully below. Alternatively, chamber 164 may include devices, suchas capacitor-forming electroplates (not shown), that sense the pressureand/or fluid flow within chamber 164 directly.

As can be seen in FIGS. 9, 10, 11 and 12, cassette 500 of the seventhembodiment of the present invention generally comprises housing 502,waste container 118, top cover gasket 136, compressible tube 518, valvemolding 262, elastic diaphragm 166, diaphragm cover 170 and bottom covergasket 184. As can be seen in FIGS. 9 and 27, cassette 500 is used incombination with a surgical instrument having console 501 and handpiece10 used by the surgeon to fragment tissue at a surgical site, supplyirrigation fluid to the surgical site and aspirate the fragmented tissueand irrigation fluid from the site. Console 501 contains display panel104 that displays the current control settings and operating parametersof the instrument. Control panel 106 on console 501 includes switches(not shown) to control the various conditions of operation of theinstrument. Start button 108 initiates operation of the instrument. Side503 of console 501 contains interface slot 505 that accepts cassette500. Within interface slot 505 are mechanisms (not shown) for holdingcassette 500 securely within interface slot 505 and actuating valves 546and 558 and for operating peristaltic pump 516. These mechanisms (notshown) will vary from console to console according to the particularembodiment of cassette 500 which is used with a particular console 501,and these mechanisms do not form part of this invention.

As can be seen in FIGS. 10, 11, 13 and 14, housing 502 consistsinterface wall 504, front wall 140 opposite interface wall 504, top 145,bottom 143, side walls 142 and is preferably constructed in one piecefrom injection molded medical grade thermoplastic. As can be seen inFIGS. 10 and 11, top 145 contains horizontal conduits 514, 544, 548, 556and 560, coupling 146 and peristaltic pump race 126. Conduits 514, 544,548, 556 and 560 are generally square channels integrally molded in top145 of housing 502. Coupling 146 is integrally molded in housing 502 andis of similar construction as coupling 506. Pump race 126 is open at top145 and is bordered on one side by wall 142 of housing 502 and on theother side by a generally J-shaped, thin wall 123 projecting upward frombottom 143 that is integrally molding in housing 502 and contains asemicircular depression 121 at the base of the J near interface wall504. Pump race 126 accepts peristaltic tube 518 having an inlet end 517that frictionally engages coupling 146 in top 145 that is in fluidcommunication with conduit 514 and a discharge end 519 that threadsaround pump race 126 and exits housing 502 at notch 600. Discharge end519 of tube 518 may be connected to waste container 118 or to some otherdevice (not shown). As can be seen in FIG. 11, tube 518 is held tightwithin race 126 by friction tabs 127 molded into race 126. In thisembodiment, discharge line 522 is not necessary because tube 518 is ofsufficient length to exit cassette 502 at notch 600.

Bottom 143 of housing 502 contains pressure sensing chamber 164 andsolid portion 133 having cassette retaining slot 134. Retaining slot 134cooperates with a cassette retaining arm (not shown) on console 501 toretain cassette 500 within interface area 505. The control arm (notshown) is operated by control lever 112 on side 503 of console 501. Ascan be seen in FIGS. 10, 12 and 14, pressure sensing chamber 164 isgenerally round and consists of a thin-walled vertical cylinder 165having a closed, slanted end 167 near top 145 and an open, generallyT-shaped end 169 having a recess 173 of slightly larger diameter thancylinder 165 proximate to bottom 143. End 167 is slanted toward port 512in chamber 164 so that air can escape chamber 164, making chamber 164self-priming. Chamber 164 communicates with coupling 506 throughhorizontal port 512 and communicates with conduit 514 through verticalport 156 that is integrally molded between conduit 514 and closed end167 of chamber 164.

As can be seen in FIGS. 10, 13 and 17, interface wall 504 contains pumpcutout 125, identical, circular valves 546 and 558 and recessed pressuresensing coupling 190. Valves 546 and 558 generally comprise flat,recessed valve faces 208 and 244 and diaphragm mounting rings 232 and250, respectively, and are integrally molded in housing 502. As can beseen in FIGS. 10, 11 and 13, valve face 208 contains horizontal inletport 210 that communicates with horizontal conduit 544 through verticalport 204 and horizontal outlet port 212 that communicates withhorizontal conduit 548 through vertical port 216. Valve face 244contains horizontal inlet port 248 that communicates with horizontalconduit 560 through vertical port 240 and horizontal outlet port 246that communicates with horizontal conduit 514 through horizontal conduit556 and vertical port 254. Coupling 190 is spaced between valves 546 ad558 and has an enlarged bore 191 open at one end that is substantiallyflush with interface wall 504 and terminating at a closed end having ahorizontal pressure sensing port 186. Pressure sensing port 186communicates with recess 173 in open end 169 of chamber 164 throughvertical bore 182.

As can be seen in FIGS. 9, 11 and 26, front wall 140 contains wastecontainer tab 602 having an eyelet 144 to which waste container 118 maybe attached, couplings 506, 532 and 538 and pump tube notch 600 fromwhich tube 518 exits housing 502. Coupling 506 is contained withinrecess 507 in housing 502 and communicates with chamber 164 throughhorizontal port 512. Coupling 532 is contained within recess 533 inhousing 502 and communicates with horizontal conduit 544 throughhorizontal port 536 and vertical port 200 in conduit 544. Coupling 538is contained within enlarged recess 539 in housing 502. Coupling 538 islarger in diameter than couplings 506 and 532 and has an internal bore529 that accepts filter element 227. Filter element 227 is retainedwithin bore 539 by filter retainer 226 having coupling 229. Filterretainer 226 may be retained on coupling 538 by any suitable means, suchas friction or suitable adhesive, and is of similar construction ashousing 502. Coupling 538 communicates with horizontal conduit 548through horizontal port 542 and vertical port 220 in conduit 548 andcommunicates with port 231 in coupling 229 on filter retainer 226through filter element 227.

As can be seen in FIGS. 10, 11, 23, 24 and 25, elastic molding 262 isgenerally dumbbell-shaped and consists of a hollow pressure sensing portnipple 192 having a bore 195 and a sealing ring 193 equally spacedbetween two identical circular valve diaphragms 234 and 258 each havinga sealing rim 236 and 260, respectively. Valve diaphragms 234 and 258each have a recessed sealing face, 235 and 259, respectively, and valveactuation surface 261 and 237 opposite valve faces 235 and 259,respectively, that contain control dimples 655. Sealing faces 235 and259 may be any suitable diameter but a diameter of approximatelyone-quarter inch (1/4") is preferred. Molding 262 can be made of anysuitably resilient material such as silicon rubber, sanoprene or J-Von.

The pressure level within conduit 514 is monitored by a pressure sensor(not shown) within console 501. To prevent contaminated fluid fromentering the pressure sensor (not shown), pressure sensing chamber 164having cylinder 165, diaphragm 166, diaphragm cover 170 and bottomgasket 184 is used as shown in FIGS. 12, 19, 20, 21 and 22. Diaphragm166 is slightly larger in diameter than chamber 164 and is made of anelastic material such as silicone rubber. As can be seen in FIGS. 19 and20, diaphragm cover 170 is generally circular, has a rounded interiorsurface 181 having a protruding rim 171 and a coupling 180 having a port178, an exterior surface 179 having support ribs 670 and radial channel176, a central port 174 in fluid communication with interior surface 181and exterior surface 179. Port 178 and port 174 communicate with eachother through radial channel 176.

As can be seen in FIGS. 12 and 20, diaphragm 166 is placed on frontsurface 181 of diaphragm cover 170 so that hole 168 in diaphragm 166fits over coupling 180 on cover 170. Diaphragm cover 170 containingdiaphragm 168 is placed in open end 169 of chamber 164 so that rim 171contacts recess 173 and coupling 180 journals into bore 182, which is incommunication with pressure sensing port 186. Bottom gasket 184, whichis round and generally the same diameter as diaphragm cover 170, isplaced on exterior surface 179 of diaphragm cover 170, thereby sealingports 174 and 178 and channel 176 into a fluid-tight conduit. Gasket 184is similar to gasket 136, may be made of any suitable material and maybe attached to diaphragm cover 170 by any suitable means. However, aclear polyester film such as that sold under the trademark MYLAR® and apressure sensitive adhesive such as heat activated polyurethene arepreferred.

In use, when pump 516 is not operating and the pressure in diaphragmchamber 164 is the same as atmospheric pressure, diaphragm 166 isrelaxed and lies taut against interior surface 181 of diaphragm cover170. When pump 516 is operating, thereby reducing the pressure withinconduit 514 and diaphragm chamber 164 below atmospheric pressure,diaphragm 166 is stretched toward closed end 167 of chamber 164 by thereduced pressure within diaphragm chamber 164. The stretching ofdiaphragm 166 creates an area of reduced pressure between diaphragm 166and diaphragm cover 170 that is communicated to external side 179 ofdiaphragm cover 170 through central port 174 and to port 178 in coupling180 through radial conduit 176. This reduced pressure is furthercommunicated to horizontal pressure sensing port 186 through verticalbore 182 in housing 502. The pressure level in diaphragm chamber 164 issensed by a vacuum sensor (not shown) located in console 501 and thespeed of pump 516 is adjusted to keep the pressure level equal to thelevel set by the surgeon with panel controls 106 of console 501. The useof diaphragm chamber 164 and diaphragm 166 provides an accurate pressuresignal to the pressure sensor (not shown) while keeping the sensor (notshown) free from contamination by aspirated fluid.

Cassette 500 is further assembled by placing top cover gasket 136 on top145 of housing 502 to form closed conduits 514, 544, 548, 556, 560.Gasket 136 is similar to gasket 184 and may be made of similarmaterials. (i.e. clear polyester film such as that sold under thetrademark MYLAR® and a pressure sensitive adhesive such as heat activatepolyurethene). End 517 of tube 518 is placed over coupling 146 and tube518 is threaded through pump race 126 until discharge end 519 exitshousing 502 through notch 600. As can be seen in FIG. 9, end 519 isconnected to waste container 118. Elastic molding 262 is placed oninterface wall 504 so that sealing face 235 lays flat against valve face208 of valve 546 and sealing rim 236 frictionally engages ring 232sealing off horizontal ports 210 and 212, sealing face 259 lays flatagainst valve face 244 of valve 558 and sealing rim 260 frictionallyengages ring 250 thereby sealing off horizontal ports 246 and 248 andhollow pressure sensing nipple 192 journals within bore 191 of coupling190 and sealing ring 193 frictionally engages coupling 190. An adhesivesuch as RTV silicone may be used to prevent molding 262 from beingaccidently dislodged from housing 502. The dual-port design of valves546 and 558 is more reliable than conventional single port valvesbecause faces 235 and 259 need only contact one port 210/212 or 246/248,respectively, to prevent flow through valves 546 and 558. In addition,the structure of valves 546 and 558 described above allows these valvesto be used to regulate flow as well as prevent flow.

In use, interface wall 504 of cassette 500 is inserted into interfacearea 505 in side 503 of console 501 so that roller head 520 projectsthrough pump cutout 125 and compresses tube 518 against depression 121in pump race 126, two valve actuators (not shown) in interface area 505engage dimples 655 in actuation surfaces 237 and 261, a pressure sensingprobe (not shown) in interface area 505 is inserted into bore 195 ofhollow pressure sensing nipple 192 and a cassette holding arm (notshown) engages cassette retaining slot 34.

Aspiration line 508, which is connected on one end to surgical handpiece10, is connected at the other end to coupling 506. Irrigation fluidsupply line 534 is connected on one end to a supply of pressurizedirrigation fluid (not shown) and on the other end to coupling 532.Irrigation fluid outlet line 540 is connected on one end to surgicalhandpiece 10 and on the other end to coupling 229 on filter retainer226.

Roller head 520 and tube 518 operate in the same manner as describedabove and draw aspiration fluid through line 508, port 512, chamber 164,conduit 514, port 146 and tube 518 where it is discharged into wastecontainer 118. The pressure level within the closed aspiration fluidsystem is monitored by pressure sensing chamber 164 in cassette 500 anda pressure sensor (not shown) in interface slot 505 in console 501 inthe manner described above.

Irrigation fluid is supplied to cassette 500 from a pressurized source(not shown) through irrigation supply line 534 and enters cassette 500through irrigation fluid inlet port 536 where it is conducted to valve546 through conduit 544. Conduit 560 branches off from conduit 544 andconducts a portion of the irrigation fluid to valve 558. In its relaxedposition, sealing face 235 on diaphragm 234 seals tightly against fact208 on valve 546 to prevent the flow of irrigation fluid throughvertical port 204 and out horizontal port 210. When irrigation fluid isneeded, the valve actuator (not shown) in interface slot 505 of console501 retracts so that the fluid pressure within the system pushesdiaphragm 234 away from valve face 208 a small amount (on the order of0.020 inches), allowing irrigation fluid to flow up vertical port 204,out horizontal port 210 and across valve face 208 where it entershorizontal port 212, flows up vertical port 216, along horizontalconduit 548, down vertical port 220, through horizontal port 542 andfilter element 227, out port 231 in coupling 229 and into handpiecesupply line 540.

When the reduced pressure within aspiration fluid conduit 514 is toogreat, as communicated to the pressure sensor (not shown) by pressuresensing chamber 164, pump 516 may be slowed or stopped. However, whenthe reduced pressure within aspiration fluid conduit 514 must be quicklyvented, an actuator (not shown) within interface slot 505 operatesdiaphragm 258 on valve 558 in a similar manner as described above toallow irrigation fluid to flow through horizontal irrigation fluid ventconduit 560, across face 244 on valve 558, into horizontal port 246 andinto horizontal conduit 514 through horizontal transfer conduit 556 andvertical port 240, thereby increasing the pressure within conduit 514.The liquid or irrigation fluid vent as herein described operates morerapidly than an atmospheric vent and has a number of advantages that aredescribed in Haines, U.S. Pat. No. 4,832,685, which is incorporatedherein by reference.

In an eighth embodiment of the present invention, illustrated in FIGS.28-32, cassette 700 contains external peristaltic pump tube 702, housing704, molding 706, front gasket 708, rear gasket 710, collectioncontainer 712 and hydrophobic filter 714 that prevents liquid fromentering vent 754 or air vent line 744. Housing 704 contains aspirationfluid inlet coupling 746, irrigation fluid inlet coupling 748,irrigation fluid outlet coupling 750 and peristaltic pump tube inlet 716and peristaltic pump tube outlet 718 that are offset from each otherrelative to front 720 and rear 722 of cassette 700. As can best be seenin FIG. 30, this offset or diagonal orientation of pump tube 702 forcespump tube 702 into winding slot 726 in roller head 724 when cassette 700is placed within interface slot 728 in the console (not shown). Whenroller head is initially rotated, winding slot 726 winds or stretchespump tube 702 over roller head 724, eliminating the need for pump tube702 to be manually wound over roller head 724. As roller head 724completes one full revolution, pump tube 702 slides out of winding slot726 and becomes fully stretched over and frictionally engaged withroller head 724.

Housing 704 may also contain capacitance chamber 730 that is closed tofront 720 of cassette 700 and open to rear 722 of cassette 700 and aplurality of irrigation and aspiration fluid flow passage formingchannels 732 that are open to rear 722 of cassette 700. Chamber 730 andchannels 732 are sealed fluid tight by rear gasket 710. As discussedabove, channels 732 are arranged so that irrigation fluid enteringcassette 700 through irrigation fluid inlet coupling 748 can be directedinto pump tube 702 to quickly increase the pressure within pump tube 702if required by the surgeon. However, the pressure within pump tube 702can be much lower than the pressure within irrigation line 734, and whenirrigation valve 752 is opened to allow irrigation fluid to enter pumptube 702, the reduced pressure within pump tube 702 can cause irrigationline 734 to act as a suction line and draw fluid from the eye. To helpprevent such an occurrence, chamber 730 acts as a pressure capacitor tosmooth out pressure fluctuations within irrigation line 734. As can beseen in FIG. 32, when irrigation line 734 is pressurized with irrigationfluid, gasket 710 expands slightly to increase the volume of irrigationfluid in chamber 730. If the pressure level within irrigation line 734drops suddenly, the elastic nature of rear gasket 710 causes it tocontract, thereby helping to maintain a positive pressure within chamber730 and smooth out any pressure fluctuations. In addition, asillustrated in FIG. 32, chamber inlet 738 and chamber outlet 733 maycontain barbs 742 that permit irrigation fluid flow through inlet 738into chamber 730 and out of chamber 730 through outlet 733 but restrictirrigation fluid flow backwards through outlet 733 into chamber 730 andout of chamber 730 through outlet 740, thereby helping to preventirrigation fluid from leaving the eye.

The invention having now been fully described, it should be understoodthat it may be embodied in other specific forms or variations withoutdeparting from its spirit or essential characteristics. Accordingly, theembodiment described above are to be considered in all respects asillustrative and not restrictive.

I claim:
 1. A cassette for use in combination with a surgical handpieceand a control console for controlling irrigation and aspiration fluidflows in the handpiece, comprising:a) a housing having an externalsurface and an interface wall adapted to be held in operativeassociation with the control console; b) a means for generating apartial vacuum through interaction with a motive force in the controlconsole having an inlet and a discharge line connected to a wastecontainer; c) an aspiration fluid inlet coupling integrally formed inthe housing; d) an irrigation fluid inlet coupling integrally formed inthe housing; e) an irrigation fluid outlet coupling integrally formed inthe housing; f) an aspiration fluid flow passage integrally formed inthe housing in fluid communication with the aspiration fluid inletcoupling and the partial vacuum generating means inlet; g) an irrigationfluid capacitance chamber integrally formed in the housing; h) anirrigation fluid inlet flow passage integrally formed in the housing incommunication with the irrigation fluid inlet coupling and thecapacitance chamber; i) an irrigation fluid outlet flow passageintegrally formed in the housing in communication with the irrigationfluid inlet flow passage and the irrigation fluid inlet coupling throughthe capacitance chamber and the irrigation fluid outlet coupling to forma continuous irrigation fluid flow passage between the irrigation fluidinlet coupling and the irrigation fluid outlet coupling; and j) a valveon the interface wall of the housing for controlling the irrigationfluid flow in the continuous irrigation fluid flow passage.
 2. Thecassette of claim 1 wherein the valve is a diaphragm valve.
 3. Thecassette of claim 1 wherein the partial vacuum generating means is aperistaltic pump tube loop projecting outward from the external surfaceof the cassette opposite the interface wall and the motive force is aperistaltic pump roller head located in the control console having apump tube winding slot.
 4. The cassette of claim 1 wherein theaspiration fluid flow passage, the continuous irrigation fluid flowpassage and the capacitance chamber comprise open channels formed in theexternal surface of the housing sealed fluid tight by a gasket adheredto the external surface.
 5. The cassette of claim 1 wherein thecontinuous irrigation fluid flow passage contains barbs that restrictflow in one direction only.
 6. The cassette of claim 1 furthercomprising a vent for venting atmospheric air to the aspiration fluidflow passage.
 7. A cassette for use in combination with a surgicalhandpiece and a control console for controlling irrigation andaspiration fluid flows in the handpiece, comprising:a) a housing havingan external surface and an interface wall adapted to be held inoperative association with the control console; b) a peristaltic pumptube loop projecting outward from the housing opposite the interfacewall and having an inlet and a discharge line in fluid communicationwith a waste container; c) an aspiration fluid inlet coupling integrallyformed in the housing; d) an irrigation fluid inlet coupling integrallyformed in the housing; e) an irrigation fluid outlet coupling integrallyformed in the housing; f) an irrigation fluid capacitance chamberintegrally formed in the housing; g) an aspiration fluid flow passageintegrally formed in the housing in fluid communication with theaspiration fluid inlet coupling and the peristaltic pump tube inlet; g)an irrigation fluid flow passage integrally formed in the housing influid communication with the aspiration fluid inlet coupling and theperistaltic pump tube inlet; h) an irrigation fluid inlet flow passageintegrally formed in the housing in communication with the irrigationfluid inlet coupling and the capacitance chamber; i) an irrigation fluidoutlet flow passage integrally formed in the housing in communicationwith the irrigation fluid inlet flow passage and the irrigation fluidinlet coupling through the capacitance chamber and the irrigation fluidoutlet coupling to form a continuous irrigation fluid flow passagebetween the irrigation fluid inlet coupling and the irrigation fluidoutlet coupling; and j) a diaphragm valve on the interface wall of thehousing spaced within the continuous irrigation fluid flow passagebetween the irrigation fluid inlet flow passage and the irrigation fluidoutlet flow passage in operative association with a valve actuator onthe console to control irrigation fluid flow in the continuousirrigation fluid flow passage.
 8. The cassette of claim 7 wherein theaspiration fluid flow passage, the continuous irrigation fluid flowpassage and the capacitance chamber comprise open channels formed in theexternal surface of the housing sealed fluid tight by a gasket adheredto the external surface.
 9. The cassette of claim 7 wherein the housingis plastic.
 10. The cassette of claim 7 wherein the continuousirrigation fluid flow passage contains barbs that restrict flow in onedirection only.